


Scientist In My Attic

by UndynesSpear



Category: Undertale (Video Game)
Genre: BaraGaster, Biting, Breeding, Broster, Chubby Reader, Emotions, F/M, I can't write smut without some plot I guess, Impregnation, Knotting, Reader Is Not Chara (Undertale), Reader Is Not Frisk (Undertale), References to Knotting, Science!Gaster - Freeform, Smut, Soul Sex
Language: English
Status: Completed
Published: 2019-11-23
Updated: 2019-11-23
Packaged: 2021-02-26 04:55:36
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 8,427
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21527914
Author URL: https://archiveofourown.org/users/UndynesSpear/pseuds/UndynesSpear
Summary: You loved listening to him talk so passionately about his work, triumphsorfailures, it made something in your chest flutter, too bad he's a player who would never be interested in you.
Relationships: W. D. Gaster/Reader, implied Grillby/reader
Comments: 14
Kudos: 396





	Scientist In My Attic

You sighed and kicked off your work shoes, blindly kicking them out of your direct path, you just got off a fourteen hour shift and you were exhausted. You were sure that would annoy your roommate later but you  _ really _ didn’t care, it was your fucking house anyway, not like  _ you _ got to work from home, you thought snarkily. You rubbed your temple and shook your head, glad your roommate was at least anal about leaving uneccesary lights off, though honestly they just forgot to turn them on to begin with. You had found them more than once sitting at the island trying to read papers by a dim battery-powered candle that was set to turn on at night. You had fun suddenly flicking on the lights and watching them grasp their eyes in pain at the sudden forced muscle flex of their eyes. You then had to sit through a very polite, but strongly worded lecture about damaging vision for a joke, though the next day for some reason all of your hair-ties had gone missing from the house and you were pretty sure who to blame. Especially when you found them all tied in a complex knot your cat was batting around the house; it took you three hours to undo. You could have just thrown them away and bought more, but honestly it was kind of fun, you liked when your roommate made little puzzles and set them around the house. Some of those puzzles were really non-lethal traps but what's a tripwire into a beanbag chair covered in flour between roommates every once in a while? Yes, you saw the hypocrisy.

You groaned dramatically like a zombie, you would go to bed soon but it had been a busy night and you didn’t get a dinner. You knew if you didn’t eat now you wouldn’t get to eat until much later and you really tried to eat at least once a day. You rubbed your stomach and made a face as you opened the fridge, not that your full figure really gave an idea at how poorly you really ate. The quality of food you chose wasn’t terrible, but the inconsistent meals probably didn’t help at all. You avoided a few of the containers on your roommates shelf, neither of you had a problem with sharing food but… there was a reason their shelf was so empty and filled with takeout containers. Needless to say, they bought most of the groceries and you cooked when you were home. Unfortunately for you, your roommate could eat straight trash (and you’re pretty sure you watched them do just that once) and not gain an ounce of fat. You pulled out a few things to make a sandwich and looked up towards the ceiling, you should check on them later when you get up, make sure they still know what the sun is and what other people are. Though honestly that last one has been in question multiple times. You’re roommate didn’t always respect boundaries, they had a habit of getting tunnel vision when they were excited about something. They had walked in on you taking a bath more than once just because they wanted to tell you about a new compound they had made or about an idea for a mechanism or trap.

Thank the stars for extra foamy bubble bath, you had honestly gotten so used to it now that you hardly jumped when the door would suddenly fly open with an excited call of your name. Unfortunately locks did not stop them, they didn’t pick the locks or anything creepy like that, they just didn’t function for them and like you said, tunnel vision. You eyed the coffee pot next to you on the counter, doesn’t look fresh, just some sludge at the bottom. You made an ick face and yanked the pot from the machine and tossed it in the sink with some soap and replaced the grounds with fresh. You washed the pot and started the coffee, finishing making your meal and watching it drip. The state of the coffee pot and the lack of takeout containers in the fridge told you all you needed to know, you roommate has not left their room in two days. You grabbed a few more ingredients for another sandwich, getting the special seasoning and sprinkling it over the whole thing before tossing it on a plate with some chisps. You grabbed a large mug of coffee, black as sin, and headed up the stairs, going past your room on the second floor you headed up the narrow steps that took you to the attic. You violently kicked the door and hollered at the occupant, “Hey, bonehead, I’m home, open the door, my hands are full.” You heard a few things fall off the desk, among them some glass beakers which immediately shattered, some mild cursing and then rapid footsteps across the wooden floor. The door was yanked open to reveal a very disheveled looking skeleton monster.

You grinned up at the tall monster who had to bend slightly to look at you from the doorway. “Rough night?” He looked down at you and narrowed his eyes, his ink-stained lab coat hung loosely around his shoulders, creased and rumpled, looking like he either slept in it, used it as a pillow, or both, his black slacks had been traded for worn black sweatpants, but he wore his usual cashmere slate-gray sweater which somehow always looked clean and fresh. Honestly you would have stolen it by now but he always seemed to be wearing it, except the one time where you had walked in on  _ him _ taking a shower on accident. He hadn’t seen you, too busy writing equations on the steamed glass of the shower, and you were glad he hadn’t noticed you, he never would have let you live that down. Yes, again, you were aware of the hypocrisy. You were sure he was about to open his mouth and say something absolutely scathing as you clearly has just woken him, but then he sniffed and his violet eyelights zeroed in on the plate and mug in your hands. 

“ **You are a beautiful goddess and every day I am blessed that you shine the miracle of your presence on my black soul.** ” You snickered, he turned into quite the poet when you fed him. He stepped away from the door and gave you a gentlemanly bow, you snorted and strode over to his poor desk. With how bowed the table was, you once again questioned allowing him to live in the attic above you instead of the basement where he couldn’t possibly break the floor. You knew exactly why though as you looked out the large window above the desk, sunlight poured through the curtains and gave the room a cheery glow. You very slowly went to set down the plate when a flurry of hands appeared and cleared a space of papers and books. You hummed and set down the plate and mug as the monster joined you at his desk. He murmured more flowery words as he dug in, you watched the sunlight play on the water of the small pond in the backyard. A moment later you heard a satisfied sigh and the scrape of a stool as he stood next to you, looking up at the sun. “ **...Do not go in your bedroom.** ” You whipped your head to the side and narrowed your gaze at the man who was studiously ignoring it. “What did you do?” He looked at you from the corner of his eye, violet eyelight sparkling with mischief. He remained silent but a small smirk had turned the corner of his mouth. You went to grab the mug from his hand, too late for the sandwich but he chuckled and held it out of reach. “Dings, I gotta go to sleeeeeep, I don’t have time for prankssssss.” He tapped his chin, like he was actually thinking of a solution that didn’t involve you playing along with his game. “ **Well, I suppose you could just use my bed.** ”

From anyone else you would have taken that as suggestive, but to you it just sounded suspicious, the skeleton had never shown romantic or sexual interest in you but he definitely has tried to make you an unknowing test subject on multiple occasions. He definitely seemed to be in a mischievous mood today so you were more likely to wake up pranked, he would most likely use blue magic to stick you to the bed and make you late for work. Which joke was on him, you had the night off and his magic just felt like a warm weight on your soul, never a bother at all. It was worse when his brothers came to visit, they would all three plot up in the attic and torture you with various pranks, traps, and in the case of the middle brother, awkward, invasive personal questions and comments. He existed purely to make you flustered and embarrassed once he realized his endless supply of puns did not phase you, but excessive suggestive comments and innuendo would get to you after a while, especially if he made it about you and his older brother when Wingdings would leave the room. His favorite being, “so, when are ya gonna make an honest woman out of my big bro, he’s a delicate flower ya know?” The youngest brother would give the middle one disapproving looks from the kitchen, telling him his grossly invasive jokes were making the food taste bad and to knock it off or he would tell their eldest brother.

You narrowed your eyes in suspicion at the eldest of the Skeleton brothers, his head finally turning towards you. “ **What? I’m offering you a solution, I can assure you the sheets are clean.** ” You snorted and crossed your arms, “Only because you haven’t slept there since you washed them last, you’ve slept at that desk if at all.” He had the gall to look unashamed, “You haven’t even gone out like you used to!” You really hadn’t seen him leave the house unless you shoved him out the door with a grocery list and his car keys in months. His gaze seemed to flicker away from you a moment before he cleared his throat, “ **You know I have no time for foolish women who have no thoughts of their own, half of them don’t know the difference between homogonized milk and homosapiens!** ” He threw his hands up in the air above you in exasperation before shoving them under his armpits and sulking. He then returned his gaze to you and smirked, “ **Why would I go after them when I have a wonderful, smart goddess such as yourself** .” You felt your cheeks pink and you stepped back as he loomed over you with a cheshire grin. He folded his hands behind his back as he advanced on you until you felt the backs of your legs smack into the edge of his massive bed. You yelped as you toppled backwards. He snickered as you sat up, annoyed, “Gaster are you serious, what is your deal today?” He chuckled and you felt a wad of fabric land on your head a moment later and his retreating footsteps. As you went to yank the offending fabric off your head you paused when your fingers touched the soft fabric of a very familiar sweater. You blinked and pulled it off carefully, it  _ was _ his sweater. You looked up as he paused by the door, tilting his head back at you. Your eyes roved over his form, you never saw him without a shirt, it was pretty much what you expected, his torso was skeletal, but the bones were larger and more fused than a human skeleton, forming more of a body mass than a human skeleton shape would. You knew his bones had some flex, more like very firm flesh and muscle after having bumped into him from time to time, these hallways were small when you added a giant male monster into the mix. “ **You can wear that since your room is unavailable for now, I’m going to take a shower.** ” 

You nodded and thanked him for the sweater as he left, you waited a moment after you heard the door click and his steady head towards the downstairs bathroom before you stripped and pulled the sweater over your head. You giggled at the softness on your skin and slipped under the covers of his bed, you pressed your face into one of his pillows and sighed, how could his bed be so comfortable? You inhaled deeply, and somehow he always smelled vaguely like coffee and peppermint, enough to were his sheets did too. You yawned and closed your eyes, sure you would wake up when he got done with his shower.

Dings closed the door to the shared bathroom and studiously refused to look at the violet flush staining his cheeks. He really didn’t deserve you, he hadn’t eaten in… days, he could see the dark circles under your eyes. You were exhausted from work and still made time to take care of him, you didn’t owe him anything, he was just the crazy monster scientist you let rent your attic. He couldn’t believe you hadn’t thrown him out on his coccyx for how he had behaved, he really had pushed you to your limits sometimes. His brother, Sans, he had yelled at one more than one occasion about his comments towards you and his brother had just asked him when his jealous bone started growing in and if all humans made him act like this or if it was just you. Dings had growled at his shorter brother in annoyance as he continued to pester him, making ‘boning’ jokes until he had handed him off like a sack of potatoes to their youngest brother, Papyrus, who would sigh in annoyance and stuffed a still chattering Sans under his arm and stomp out the door berating the middle brother. “ _ *snort*b-b-but bro! how did the skeleton and the human have sex? they  _ **_boned_ ** _! _ ” Papyrus would shriek and violently toss the shorter skeleton into the car and then drive very safely away obeying all traffic laws but screaming with every shitty pun, terrifying pedestrians. Still before he had gotten to know you he had behaved rather inappropriately and still did from time to time much to his mortification.He stared at the bathtub under the large bay window and felt his cheekbones tint darker. He turned and stripped the rest of his clothes, hooking his royal purple towel on the hook next to yours, you always did really like that color, he thought as he touched your towel for a moment, a few things around the house, even a couple walls were your favorite color. It wasn’t always conventional for where you chose to express it, but somehow it worked. Not that he was some sort of interior design pro, the most color he owned was that towel and a few other things you had bought him, claiming it matched his eyes.

With one last shameful look at the free-standing bathtub he stepped into the shower and embraced the initial cold of the water which swiftly heated to a scorching temperature. He rested the front of his skull on the tiled wall, letting the water wash down his body, he had this terrible habit of getting tunnel vision when he got excited about something, he would ignore anything and everything in his mission to complete his goal, which was usually finding you to tell you about a discovery he made or a failed experiment. Unfortunately it also allowed him to ignore the fact you may be doing something private like taking a bath,  un luckily he hadn’t walked in on you taking a shower because that would be… well, it would be… he swallowed heavily. He knew you had walked in on him once taking a shower, you had stared for so long he had started doing equations on the shower walls to distract himself until you left, luckily math wasn’t your strong suit or you would have seen his math made no sense. He made a face as he realized he may have written 2+2=5 at one point, math wasn’t your best subject but you weren’t  _ stupid _ . He thonked his skull against the tile in embarrassment, there's no way you would have been distracted by his body, it was just bones after all. He cracked open a socket and looked down towards his hips, well,  _ most _ of him was. You had been right, he hadn’t gone out lately, before he didn’t care about their intelligence, it's not like he would be seeing them again after all. But something had changed and that hadn’t been enough, he started being more selective but still something left him feeling more hollow than before. It had been after reflecting on one of his manic tunnel vision episodes did he realize what the problem was.

His eyes landed on the tub, obscured by the steamed glass. He had done it! He had made a stable pocket dimension- well, for a few minutes at least  _ and _ he hadn't made the whole house collapse into a singularity! He threw up his fists in victory and jumped up from the desk, he  _ had _ to tell you, you would be so excited! He loved how enraptured you looked when he told you about his experiments, the way your eyes sparkled… He ran down the stairs, following his sensitive hearing and sense of smell to find you, he could feel the magic dipping off him in excitement. He finally found the door hiding you and entered without thought, his magic flicking the lock open. He had thrown the door open and grinned when you turned towards him, shriek caught in your throat. Your hair was piled on top of your head, majority of your body submerged in the large soaking tub, bubbles obscuring everything but your shoulders and collar bones. At the time he hadn't really noticed and launched into his science jargon. Your expression had paled when he mentioned the singularity possibility but had held your questions. He watched as you relaxed, becoming more interested in the talk until you started to shiver. He had flushed when he realized he had walked in on your bathing time and swiftly made an excuse for his exit.

He had swiftly returned to his room and sat at his desk, frozen, he sat silently in the dark, the image of you naked in the bathtub burned into his sockets. He considered himself a confident man, knew what he wanted and went after it, going to any lengths to get it, but he found himself hesitant when it came to you. He had to admit he had never looked at you properly as a woman, and he really should have. When he had been looking for a suitable place to live, closer to the labs on top of and under Mt. Ebott, he had run into a bit of trouble. If they would rent to a monster they definitely weren't okay with the random explosions and smoke alarms being set off at all hours. You had been a star-sent goddess in his eyes, he had been lamenting his woes to a friend while he was at work and you had overheard his dilemma and offered him the room. His friend had silently vouched for you over your shoulder and he accepted the offer to take a look.

He had offered to walk you home as it was late and the bar was closing, you had hesitated for a moment but seemed to realize it would soon be his home and took him up on the offer. As he helped you into your jacket, always the gentleman, his friend, the fiery bartender had watched him carefully. Grillby knew Wingdings was a bit of a womanizer… okay, a  _ complete _ womanizer, and he didn't want you to fall prey to his charms. You were a nice human girl, Grillby had once tossed the idea of asking you on a date around in his head but you never gave him any signals you were interested in anything except friendship. He caught Dings' eye as he left and gave him a  _ look _ , which sounds hard to do as a fire elemental who only bothered forming a face for these specific reasons, but the message was received… he hoped.

After helping you home you showed him the space. He had walked around, looking at the open space and smiled, tiny violet stars in his sockets. It was perfect, and you didn't mind that he was a monster, (nope), or the explosions! (You actually minded those very much). You had stood by the open door and grinned, you had always admired his enthusiasm for things. Grillby had of course already warned you away from the scientist, when you had listened to him rant and rave about about his dimensional box project you had been hooked and had asked Grillby who he was. He had given you a stern look and you rolled your eyes, the man acted like you had nothing but candy storage up in your skull. You obviously didn't have candy up there, but sometimes you wonder if it would make life seem  _ sweeter _ if you did. Honestly when Wingdings moved in you hadn't really believed Grillby about the skeleton monsters revolving door of women. A few weeks went by before he returned home with a giggling human woman, and you did not get a wink of sleep. This pattern continued for three more days and as many different women before you had snapped.

Four in the morning rolls around, and you knew it was four because you got woken up,  _ again.  _ You heard the slow, clumsy steps of a drunk human woman, followed by high-pitched giggling. You groaned into your pillow, this one had the  _ most _ annoying voice you had ever heard. That was  _ it _ , he wanted to repeatedly come home at odd hours, drag strange women with him and then proceed to have  _ the loudest fucking sex on the starsdamned planet. _ Well, you never heard him make a sound except for some quiet murmuring, but the women screamed like he was fucking their soul right out of their bodies. For all you knew when it came to monsters, having never slept with one, that could be exactly what was going on. You had violently thrown your covers off and ripped open the door to your room just as he was about to pass with his nightly prize when you shoved him in the chest against the wall. "What the actual  _ fuck _ , Gaster?" His sockets were wide, eyelights pinpricks in shock. "I can't keep doing this, you're out all fucking night, sleep during the day, which you know I dont have a problem with but you cant do  _ this  _ to me every night!" You gestured vaguely at the woman standing slack-jawed off to the side. Wingdings' expression had relaxed when he realized you were the one who had managed to shove him against a wall. He paused and took in the dark circles under your eyes, his teeth parted and he frowned. " **You are completely right, my Dear, I apologize, this has been highly inappropriate of me.** "

"Oh my god, are you married? Is this your  _ wife _ ?" The woman in the tight red dress shrieked, then she took you in and got a smug look on her face, "Well, I can see why you would want to  _ trade up _ ." You just chuckled, these sorts of girls weren't worth an ounce of your time, taking cheap shots at appearance, making  _ ass _ umptions. Honestly you felt bad for her, you wondered if she knew he was a player, though by that comment she could at least piece a few things together, even if she was completely wrong. "We just need to have a discussion about it." You said to the monster in front of you, ignoring the woman trying to glare a hole through your face. He nodded reasonably, "but not tonight, I'm so fucking exhausted," you bemoaned, he chuckled and smiled warmly, " **Then I shall let you go back to bed, I promise to make it up to you, my Dear** ." He leaned forward and pecked your forehead with his teeth in some drunken attempt at affection. You waved him off with a small smile of amusement and a roll of your eyes and shuffled back to your room, hearing the shrieking woman being led out the front door you finally drifted off to sleep, not noticing the monster peeking in on you before silently walking upstairs.

As he toweled himself off, he rubbed the fluffy towel down his face and looked at himself in the mirror. Why did he give you his sweater? It didn't bother him that you were wearing it, but it did something funny in his soul knowing you were in his bed in nothing but underclothes and his sweater. He had admired your figure on more than one occasion when you weren't looking since that day, and had tried a few subtle hints and not so subtle hints, but you had always seemed like you thought he was joking or it seemed to go over your head. So imagine much to his surprise when you agreed to sleep in his bed without much of a fight. As he stepped out of the bathroom he looked at the door to your bedroom, he was surprised that you hadn't even gone to your room to see if he had in fact done something. Though, some of his pranks you definitely wouldn't have been in the mood for after a long shift, though this one was relatively harmless, it would have just made a huge mess. He would clean it up later, but now he had a gorgeous, smart, human woman in his bed wearing  _ his _ clothes.

He felt his chest rumble, and it wasn't just  _ any _ human woman, it was the human woman he had somehow fallen for. He climbed the stairs slowly, like the monster he was, violet eyes glowing like fire as he confidently ascended the stairs. Loose black cotton pants hung low around his hips, there being a bit more bone to hold them up compared to his brothers. He was still shirtless, not seeing the point as he usually slept without it anyway, and it was one less article of clothing to remove later. Oh he had seen you stare as he left the room, he had seen that on plenty of womens' faces, monster  _ and  _ human, you were interested,  _ very _ interested. Who was he to deny you  or himself ?

As he silently opened the door to his room he noticed you curled up under the covers, your curvaceous form filling out his sweater better than he ever could. No other women had worn his sweater, it meant too much to him to allow some woman he would never see again to wear it. It had been a gift from his brothers after they all got to the surface, his old one… well… it's hard to remove other dimensional stains. It set his soul afire to see you in his sweater, you snored softly in your sleep and his soul was flooded with warmth. No… you were much too tired for something like this, but maybe he could just lay next to you for a few hours.

You awoke warm and comfortable, a very firm but pliable pillow was being hugged to your face, you peeked open an eye to see the room still dark and went back to sleep, giving your breathing pillow a squee- wait. Breathing? Your eyes shot open and you froze.  _ Oh stars, where am I, this isn't my bed, did I get trashed last night? Who the fuck is this? _ Your eyes were wide as you took stock of the situation, they darted around the room for anything familiar. Beakers, quantum physics text book, screaming rubber chicken-  _ I'm in Dings' room.  _ You relaxed as your brain caught up with you and you remembered he had fucked with your bedroom so offered you his. You sighed and relaxed- wait. You felt your fingers gripping thin, warm, bones, you looked up and saw the sleeping face of Wingdings Gaster Skeleton, his even breaths stirring your hair slightly. Your face pinked as you tried to remember him getting into bed with you and vaguely remembered a deep male voice telling you to move over and complying. You did tend to cuddle things in your sleep sometimes and a large skeleton monster was apparently no exception. As you went to move away out of embarrassment you felt his arm around your back tighten and the hand you suddenly realized was gripping your ass hauled your hips firmly against his with a groan. You whimpered slightly as the movement had ground your core against something that was decidedly  _ not _ bone, but about as hard.

Wingdings woke as he squeezed the warm body in his arms, odd, he never let them stay the night. Then he heard the low feminine whimper and his eyes flickered open. Oh. You were in his arms, pressed against him, thick flesh grasped in his hands. You were looking up at him, face flushed, biting your lip, hips pressed tight against the length of him- his member gave a throb at the realization and he groaned as you gasped. " **Well,** **_good_ ** **morning, my Dear.** " You flushed as he growled low in your ear. " **Have to say, this is probably the best way you've ever woken me up** ." He purred against your neck.

"Uh you know it's me, right?" He huffed against your skin, " **Of course, how many other women have I allowed to wear my favorite sweater or actually** **_sleep_ ** **in my bed?** " Well, he had you there. You clicked your jaw shut until his hand shifted over your ass where the sweater had ridden up on one side. You tried to squirm away, why was he being like this towards you, he had never actually made a move on you, just jokes here or there, he couldn't actually be into you could he? No, that would just make you the next in a long line of his conquests. "Hey let me go, go find some floozy to mack on you nerd." He sighed in exasperation as you pressed your hands against his face in some weak attempt to push away from him. "Just coz you haven't gone out in a while doesn't mean I'm up for grabs, literally or figuratively!" You squeaked out the last part as he grabbed two thick handfuls of your flesh and pressed his teeth to your neck, dodging your hands.

" **Maybe I don't want some floozy to mack on.** " He mocked your words and you giggled unexpectedly, it sounds ridiculous coming from him. Slang and the scientist didn't always mix. " **Maybe I want the smart, beautiful, and kind woman in my arms?** " Your breath caught in your throat as his teeth lightly pinched the skin of your neck. "Flattery gets you nowhere, doctor." You deadpanned. " **Hmm, you still dont believe me. I suppose that's fair, I haven't shown you the best side of me.** " You leaned away and frowned at him, that wasn't true at all. You thought that you got to see a very special side of the man, ironically the  _ human _ side. You watched him make mistakes, get excited at his triumphs and failures, drunk off his ass at three am trying to make you dinner, Dings could not cook to save his life to begin with but somehow it was decent that time. Maybe it had been the pleased, and slightly tipsy, expression on his face as he watched you take the first bite. It could have been ash and dirt in your mouth for all you knew, the joy on his face was enough for you to choke down a bowl of broken glass and rusty nails if he said he made it for you. You tipped his chin to look at you and told him so.

"But that doesnt mean I want to just be another night to you. I'd rather stay as we are than well…" he hummed and grinned down at you. " **So, correct me if I'm wrong, if I want you to be mine for more than just tonight you would say yes?** " You narrowed your eyes up at the monster who had made no motion to release you. "Dings really? I dont play games like this, I refuse to be hurt like that." He frowned, you didn't understand what he was saying, you  _ still _ thought this a joke. " **I'm being serious. Have I brought anyone home or gone out since that night?** " You knew which night he was talking about and closed your mouth, he hadn't, you have just commented on that earlier. "...no…" he raised a brow at you and you fidgeted. Time to pull out the big guns. " **I saw you you know. That time I was in the shower.** " Your face erupted in flame anew. You tried to shrink down and cover your face with your hands "Noooooo!" You moaned in embarrassment. He chuckled and nuzzled your neck, " **I suppose it's only fair with all the times I have walked in on you.** " You grunted at that and gave him the eye. "Pervert." He kissed your neck and watched your eyelids flutter.

" **Will you be mine, Dearest?** " You sighed and opened your eyes, searching his for dishonesty and found none. "I…" His teeth joined his lips and it caused you to stutter. "Um.." he chuckled and nipped your neck. "Yes?" He paused and leaned back to look at you. " **That sounded entirely too unsure for my tastes.** " You bit your lip and he sighed, hands releasing you as though to get up and your arms looped around him in response. His eyes twinkled as he looked down at you and replaced his hands on your body. " **I'm all ears, Dearest** ." He teased you, "If you're being serious about this, I'm willing to try." You finally said.

He grinned widely before capturing your lips in a fiery kiss. Your eyes widened before you relaxed into the kiss, his tongue sweeping your bottom lip. He growled against your lips as you resisted him, roughly grinding your hips against his. Warmth spread through your abdominals at the friction and you moaned, Wingdings seeing his chance nipped your lip in punishment before wrestling his tongue with yours. The arm around your waist wandered from your back and started sliding up the side of your body exposed by the sweater. You squirmed a bit and leaned back from the kiss. "I… didn't think I was your type." He scoffed and gave you an incredulous look.

" **Not my type? What, gorgeous? Funny? Smart?** " You slapped a hand over his mouth and he nipped at your fingers. "No… fat." You didn't look away, you were not ashamed of your body, you just knew what kind of women he brought home. He rolled his eyes towards the ceiling in exasperation before pulling your hand away and flipping your positions, him pinning you to the bed. " **Dearest, I have never been one to base my attraction solely on appearance and even if I did you are still quite the fetching woman.** " He looked down at you skeptically, " **I should be the one questioning you, look at me, I'm practically bone and well,** " he gave you a cheeky shrug. " **not much else** ." You frowned up at him.

"Dings you're the smartest guy I know, I love the way you light up when you talk about your experiments and ideas. Honestly that's what made me offer you this room. I doubt you noticed me but I listened to you talk for hours about your research at the bar," you chuckled, "Grillbz even tried to warn me away from you." Wingdings smiled, sockets lidded, " **Of course I noticed you the very first night you sat at the end of the bar talking with Grillby before I walked in.** **He gave me** ** _quite_** **the nasty look when he spotted me if I recall. I couldn't figure out why until I heard you laugh and you turned towards me.** " You had been one of the most gorgeous women he had seen in his life. It hadn't been what you were wearing, it wasn't even your body or your features (though he was not lying when he said you were physically attractive as well) but the laughter and contentment with life that shone from your soul through your eyes. He had felt like a man who had been away from home for years and just stepped foot through the front door. Grillby had given him a harsh glare and jerked his head to the other end of the bar, away from you. " **After you left that night he threatened to remove my skull and jam it- well, he did not want me perusing you. He said you were too good for me.** " You glared, you were going to give that fiery asshole a piece of your mind, who the hell does he think he is? " **At the time, he was right. I would have ruined the best thing to happen to me in years.** " He stroked your hair wistfully, " **You still are way too good for me.** " 

"I'm gonna dump a bucket of water on that asshole." Gaster chuckled and tipped your chin up. " **He may be a narcissistic asshole but he is still my best friend.** " You rolled your eyes and tried to bite at the fingers pinching your chin. " **Now, where were we?** " His eyelights hungrily scaled down your body, still half covered by his sweater. " **Though I do love you in my clothes, Dearest, I think I might prefer you put of them** ." You yelped as the sweater vanished from your body, exposing your bare upper half to his gaze. He practically purred when his hands made contact with your soft flesh, he gently rolled your nipples in his fingers as you arched up into him. " **So responsive…** " he ground his hips down into yours and you parted your legs in response. Wingdings groaned at the heady heat of your core pressing against him through the thin cotton of his pants and your panties. He leaned forward and licked the space between your breasts and a deep pleasant throb responded on the other side of your skin. A surprised gasp left your lips and he repeated the motion, but gently scraping his teeth along your skin. You pressed your chest closer to his face as the hot feeling in your chest almost boiled over. Wingdings groaned as a tingling warmth grew on the surface of your skin, a deep glow emanating from the other side of your skin, taunting him.

You opened your eyes to see a deep glow dancing across the surface of your skin, the color mixing with the glow from his tongue, casting deep shadows across his face as his eyelights rolled up towards you. He ground his hips against yours and you moaned, wrapping your legs around his hips as the glow at your chest concentrated. A tweak of his fingers on your nipples and well-timed scrape of his teeth had you gasping as the burning pressure in your chest seemed to release. Gaster groaned as the small gem-like soul floated in front of him, glittering with magic, color saturated with desire and arousal. He was surprised, not expecting  _ that _ to be your main trait, but it explained a lot. It was the most gorgeous thing he had ever seen, he gently raised a finger to your soul as your eyes stared transfixed. “Is that my-” You collapsed back onto the bed with a ragged moan as his finger brushed the surface of your soul, your hips pressing flush against his, fingers twisting in the sheets. Colors exploded behind your eyes, it felt like he had just turned your entire body into a giant endogenous zone, zaps of pleasure racing across your skin just from that small touch. When you finally managed to open your eyes again you saw devious purple eyelights staring at you over the top of your pulsating soul, hovering over the surface of his hands. “What-” You shrieked in pleasured outrage as Gaster drug his tongue over the surface of your soul.

You were gorgeous, head thrown back in pleasure as you still tried to glare at him, he just couldn’t resist after seeing how sensitive you were. For some monsters, soul-play was just as good as sex, and it seemed to be true of humans too. Your soul was now dripping magic, soaking his tongue with the warm, tingling substance. You were sweet with a bite, he wondered if you tasted the same  _ other  _ places. You gasped as you felt fingers teasing your entrance, coating themselves in the embarrassing amount of wetness available. “D-Dings- oh  _ fuck _ .” He slid two thick fingers inside you roughly, your hips jerking against the palm of his hand. He hummed in pleasure, tip of his tongue grazing your quivering soul. “ **So tight, Dearest, but you’re so wet. I think you might be able to take** **_all_ ** **of me.** ” He added a third finger and a swirl of his tongue on your soul and you almost seized up. He was going to ruin you for anything or anyone else, and you were oh so ready to fall on that grenade. He twisted his fingers and set his teeth against the underside of your soul and you saw stars in a blinding white as you came with a shriek of his name. Gaster moaned, noisily lapping at your soul, magic dripping down his arms in sparkling rivers as you came around his fingers.

As the stars finally cleared from your eyes you met the expression of a very satisfied looking skeleton monster. He was practically purring as his fingers gently skated the surface of your soul and body, both reacting with small spasms of pleasure. With another lingering lick he raised himself up over your body, revealing his thick glowing violet member. “ **You are going to feel so good wrapped around me, Dearest.** ” He groaned as he pressed the thick head against your soaked core. You moaned as a warm tingle emanated from where he touched you, causing you to try and press down on him. “ **So eager…** ” He growled, stroking your soul as the thick head of his cock pressed inside your soaked entrance. You gasped as the stretch, the burn made you moan as your walls clenched. Gaster grunted and grabbed your hip in a bruising grip, seeming to be forcing himself to go slow. “ **I fear that no matter how gentle I am with you, my Dear, you will be quite** **_sore_ ** **in the morning.** ” You gasped as he punctuated his statement with a rough thrust, burying half his length inside you. He groaned as wetness flooded out around him, “ **Though you seem not to mind.** ” He rolled his hips against yours and flicked your soul with his tongue as you shuddered. Your hands threaded through his lower ribs and he groaned, melting against you, burying himself to the hilt with a hard thrust.

Your hards spasmed hard around his ribs at the twinge of pain followed by the hot burning pleasure of his teeth nibbling on your soul. His teeth set in a bit harder in response and your legs locked around his hips. He groaned and found his length deep inside you as you felt something dripping down your hands. You opened your eyes to see deep violet magic staining your arms as it dripped from the soul sparkling underneath his ribs, the magic coming off his soul a blinding white which turned to violet as it reached your skin. You grinned up at his wrecked expression and gently scored your nails along his bones, the magic making your hand slide easily across the porous surface. He grunted and narrowed his sockets at you, “ **Don’t tease a monster, Dearest.** ” He warned with a look full of promise. He pulled out of you before gripping your hips and giving you a deep thrust, you gasped as you felt small ridges rub at your clenching walls. He started a brutal pace, you were sure to have bruises, but you didn’t mind as he handled your body like one of his projects, carefully and confidently. He palmed one of your generous breasts, enjoying how they moved with each of his thrusts. Paired with your tight body around him and your wrecked expression, covered in a mix of his and your magic, he wanted more.

He roughly rubbed the pointed bottom of your soul as he worked his hips deep into yours, adjusting his angle where you cried the loudest for him. He groaned as you seized around him, walls clenching tight, he thrust as deep as he could and held the position as you screamed out his name in pleasure as you came. He panted above you as the base of his cock started to swell, his bones felt hot as you pressed back against him gasping at the unexpected sensation. Your eyes snapped to Gaster’s as he sweated above you, eyelights fuzzy upside down hearts as he ground what felt like his swelling length deeper into your already abused body. “D-Dings, what- how can you possibly get  _ bigger _ ?” He let out a deep, halting chuckle and gave your soul another swipe with his tongue, dragging a ragged moan from you as your hips jerked up onto his. “ **What can I say, Dearest, you bring out the** **_monster_ ** **in me.** ” You groaned at the awful pun which turned into a cry of pleasure as you found yourself face down, hips poised in the air as he gave a shallow thrust, the knot forming at the base rubbing the spot inside you the made you see stars. Your hands clawed at the sheets as he ground his hips against yours, his knot impossibly swollen inside you, and backwards pull of his hips taking you with him. The pliable ridges rubbing roughly against your walls along with the filthy things he was growling against your ear as you clenched around him made you throb with desire. “ **You take all of me so wonderfully my Dear, fit like a glove, love the way my magic stains your skin and how you look swollen with my knot.** ”

He felt like he was on fire, your cries beneath him as you wordlessly begged for more about drove him to the edge. He wasn’t lying when he said you brought out the monster in him, and he knew why, but didn’t want to scare you, so he figured he would tell you after. Not like you could say no after this mind-blowing sex, he  _ never _ knotted a woman, none had ever enticed him so in all his years. You looked so beautiful, he couldn’t wait to see you swollen with his children, he groaned and thrust deep inside you as magic poured from his soul behind his ribs, running down his body in violet starlight. His eyelights found their way to the crystalline soul floating above you, casting its light over you both and ran his tongue across his teeth. You both needed just one last push, coming to a decision he drew his hand over his chest and pulled out the inverted pure white soul, violet sparks leaving tingles across your back where it hovered. “ **Are you ready Dearest?** ” He panted as he drew your souls close together, he felt you clench under him, feeling the proximity of your souls. A destroyed moan was his only answer as he pressed your souls together, he let out an animalistic growl as he felt his soul flood with your arousal and affection for him, white hot pleasure drowning out anything else he may have felt as you came with a scream of his name. Gaster snarled and buried his teeth in your neck, hips pressed hard against yours as magic flooded you with white-hot tingles.

When your senses came back to you, you groaned at the thick length still throbbing inside of you, massive skeleton monster half collapsed on you panting. “Dings you’re too heavy.” He grunted and shifted slightly, the knot lodged inside of you making you both groan as it pulled on you roughly. Gaster’s hips jerked forward of their own accord and you moaned in soreness, “Ugh, careful!” He huffed and wrapped a hand around your hips and pulled you with him to lay on your side next to him, he moaned as a new flood of wetness coated his throbbing length from the new angle. You panted as he made lazy thrusts inside you, the soreness ebbing and soon you were on top ready for more. “ **My Dear you are too perfect-** ” He moaned loudly as you ground down on him, his sockets flickering open when he felt a soft touch roll down his body. His eyelights landed on the inverted soul hovering in your hands. You gave him a smirk before carelessly dragging your tongue across the surface. Gaster jerked against you, roughly grabbing your hips and pulling you down on top of him. You moaned loudly against the surface of his soul and he cursed, flipping you back beneath him as his swollen knot rubbed inside you. His pace was punishing as he made you see stars for the third time that night, growling promises against your skin until he flooded you once again with his magic.

You gasped for breath as he slid from your body as he was finally sated and collapsed beside you with a groan. You were right, he had ruined you for anyone, even with how sore you were you were already contemplating another round. “ **Dearest, you are** **_insatiable_ ** **.** ” The monster teased as the smell of you arousal stained the air anew, you flushed and went to turn away but found yourself pressed once again into the mattress, “ **Just my type** .” You moaned as once again he filled you, you had a feeling you might have to call into work tomorrow… or the next week.

**Author's Note:**

> This will probably just be a one-shot. Needed to get my Gaster fix ;)
> 
> Hopefully updates will be out soon for my other fics, just stuck on a few plot points.
> 
> As always  
> Coolest Dump  
> UndynesSpear.tumblr.com


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